1. Field of the Invention
The present invention relates to a memory apparatus of a digital video signal, in particular, the apparatus having a signal processing circuit that restores an encoded video signal on real time basis, the signal processing circuit being built in an IC circuit.
2. Description of the Related Art
As display data for a color video display in for example computer graphics, tone values of three primary colors R (red), G (green), and B (blue) of a color picture are digitized. The number of colors that can be displayed depends on the number of bits of the display data.
In conventional computer graphics systems, the number of colors that can be displayed per pixel (this number is also referred to as color display performance) is for example 256 (=28). However, when a color picture with a high color display performance that is captured by a color video camera, a color image scanner, or the like is displayed, it is insufficient to display it with a display performance of 256 colors. To improve the display performance, for example eight bits are assigned to each of three primary colors R, G, and B (thus, a total of 24 bits are assigned as display data to each pixel). Thus, a color display performance of 224=16,777,216 colors is obtained.
However, in a high resolution display unit with for example 2048xc3x972048 pixels, if 24 bits are assigned to each pixel, the amount of data necessary for displaying one color picture becomes huge as calculated in the following.
Such huge data is not easily stored in a memory, a record medium, or the like. Thus, even with a hard disk, only several pictures can be stored. In addition, to send and edit the data, it will take a long time. Thus, it is considered that this method is impractical.
To solve this problem, the number of bits per pixel is suppressed to for example eight bits. In addition, 256 colors are selected from many colors so as to display as many color as possible. The selected colors are used in a form of a conversion table that is referred to as a color look-up table (CLUT). Application software is modified so that it only uses the selected 256 colors. In this method, normally, such a look-up table (LUT) comprises an input data register, a data conversion memory, and an output data register. However, when the look-up table is used, 256 colors are selected from for example 224 colors. The selected 256 colors are displayed at a time. Thus, when more colors than 256 colors are required, this method is insufficient.
To solve such a problem, the applicant of the present invention has proposed a technology disclosed as U.S. Pat. No. 5,142,272 (issued on Aug. 25, 1992) (corresponding to Japanese Patent Laid-Open Publication No. 63-287992). The proposed technology is a color restoring apparatus. In the color restoring apparatus, with display data of a color picture composed of data of a color with the maximum tone change of adjacent pixels and data of an identification code that represents the color, data that is read from a display memory corresponding to the identification code is maintained until data of the same color is read from the display memory. Thus, with the color restoring apparatus, data can be converted into data with more bits than the original data through a mapping operation.
According to the color restoring apparatus, since a video memory only stores display data, the required capacity of the memory can be prevented from increasing. For example, in an application as with a computer game, a required number of digital pictures are written from a CD-ROM to the memory. The application software accesses the memory so as to display pictures in full colors.
Generally, when the conversion table referred to as the look-up table (LUT) is used, the memory that stores the video data and the conversion table are structured as different IC circuits. Thus, the space necessary for the IC circuits adversely increases.
In the color restoring apparatus that restores color compressed video data, a memory that stores the color compressed video data and a signal processing circuit that receives data read from the memory and generates full-color video data as with the structure of which 24 bits are assigned to each pixel are structured as different IC circuits. Thus, the space necessary for the IC circuits adversely increases.
Moreover, since a memory apparatus for use with conventional computers can be random-accessed, an address signal should be generated. Thus, an address generator that generates the address signal for random-accessing data of the memory is required.
Therefore, an object of the present invention is provide a memory apparatus of a digital video signal, the memory apparatus having a signal processing circuit that restores encoded video data in such a manner that the signal processing circuit is disposed on (built in) a semiconductor substrate of a video memory IC circuit that has a memory that stores the encoded video data, thereby reducing the size and cost of the apparatus.
Another object of the present invention is to provide a memory apparatus of a digital video signal, the memory apparatus having a signal processing circuit that restores compressed video data to data with a plurality of components in such a manner that the signal processing circuit is disposed on a semiconductor substrate of a video memory IC circuit that has a memory that stores compressed video data represented with the plurality of components that have been encoded therewith, thereby reducing the size and cost of the apparatus.
To solve the above-described problem, the present invention is a memory apparatus of a digital video signal for storing color compressed video data, the color compressed video data being compressed video data that represents components of three primary colors, the memory apparatus comprising a memory portion for storing the color compressed video data and a color restoring portion for restoring the color compressed video data into original video data, wherein the color restoring portion is disposed on a semiconductor substrate that is used in common with the memory portion. Thus, the scale of the hardware can be reduced. In addition, the space of the apparatus can be reduced.
The present invention is a memory apparatus of a digital video signal for storing input data, the memory apparatus comprising a memory portion for storing the input data that is represented with a plurality of encoded components that have been encoded therewith, and a restoring portion for restoring the compressed video data to the original plurality of components, wherein the restoring portion is disposed on a substrate that is used in common with the memory portion.
The present invention is a memory apparatus of a digital video signal for storing input data, the input data being compressed video data, the memory apparatus comprising a memory portion for storing the compressed video data, and a restoring portion for restoring the compressed video data to an original video signal, wherein the restoring portion is disposed on a substrate that is used in common with the memory portion. Thus, since the data is compressed, the storage capacity of the memory can be reduced. In addition, the scale of the hardware can be further reduced. Moreover, the space of the apparatus can be reduced.
The present invention is the memory apparatus further comprising an address generating portion composed of a counter, wherein the counter is adapted for receiving a clock pulse and a reset signal and generating an address signal corresponding to a horizontal scanning operation and a vertical scanning operation of a television with the reset signal and the clock pulse. Thus, since video data is read from the video memory corresponding to the horizontal scanning operation and the vertical scanning operation of the television, the address generator can be simply composed of a counter or the like that uses the reset signal and the clock pulses.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.